Prosthetic feet are well known in the art. In use, such prosthetic feet typically do not replicate the action of a real foot and can generate “kickback” or “kickforward” reactions that increase the risk of injury to an amputee utilizing the foot. Kickback is motion created by the prosthetic foot in a backward direction during the walking cycle. Kickforward is motion created by the prosthetic foot in a forward direction during the walking cycle. Either motion may create instability for the user if expanding or restricting the intended motion. Further, many prior art prosthetic feet generate vibrations that can travel through a user's leg and cause discomfort.
For an amputee, losing bipedality may produce an involuntary anterior lean or shift, forcing a constant imbalance or rebalance of posture. The amputee no longer possesses voluntary muscle control on his involved side due to the severance of the primary flexor and extensor muscles. The primary anterior muscle responsible for dorsiflexion (sagittal plane motion) is the anterior tibialis. Dorsiflexion is the voluntary ankle motion that elevates the foot upwards, or towards the midline of the body. The primary posterior muscle responsible for plantarflexion is the gastro-soleus complex. It is a combination of two muscles working in conjunction: the gastrocnemius and the soleus. Plantarflexion is the voluntary ankle motion that depresses the foot downwards, or away from the midline of the body. Therefore, it is desirable to have a prosthetic foot configured to promote increased muscle activity and promote increased stability for amputees, and it is desirable to provide an improved prosthetic foot which would better replicate the action of a true foot. Furthermore, it is desirable to provide an improved prosthetic foot which minimizes or eliminates “kickback” forces when the foot is utilized to walk over a door jamb or other raised profile object on a floor or on the ground, as well as reduce vibrations.
In use, such prosthetic feet are typically mounted to either an above knee amputation or a below knee amputation and are designed to mimic the natural gait of a user. Depending on the type of amputation, different types of mounting systems may be utilized. For example, if the amputation is above the knee, various suspension systems may be utilized in conjunction with the prosthetic foot to enhance the feel, fit, and function. An above the knee amputation allows for multiple options as there is significant space between the residual limb and the prosthetic foot. With a below the knee amputation, depending on the location, there may be less space between the user's residual limb and the prosthetic foot thereby allowing for different attachment configurations for the prosthetic foot.